patches.renesas/0287-xhci-Giveback-urb-in-finish_td-directly.patch

From 808d84c901a67a719ae7ca3cba5ef598cbefb3e6 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman@linux.intel.com>
Date: Fri, 11 Nov 2016 15:13:23 +0200
Subject: [PATCH 287/299] xhci: Giveback urb in finish_td directly

mostly refactoring and code cleanup.

while handling transfer events we used to check the return value of
various functions to see if we can give back the URB.
Turns out the only case when those return values are set are when
finish_td() notices we are completing the last td in the URB.

give back the urb directly in finish_td() instead.

Only functional change is that we now increase the event ring dequeue
pointer in sowtware after giving back the URB. This should not matter
as we are in hardware interrupt context and the time when writing the
new event ring dequeue to hardware remains the same.
Hardware is the only one that can put event TRBs on the event ring.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 0c03d89d0c71722dfc0c4a2a300bff37324541dc)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
 drivers/usb/host/xhci-ring.c |   31 ++++++++-----------------------
 1 file changed, 8 insertions(+), 23 deletions(-)

--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1869,7 +1869,6 @@ static int finish_td(struct xhci_hcd *xh
 	int ep_index;
 	struct urb *urb = NULL;
 	struct xhci_ep_ctx *ep_ctx;
-	int ret = 0;
 	struct urb_priv	*urb_priv;
 	u32 trb_comp_code;
 
@@ -1939,7 +1938,6 @@ td_cleanup:
 	urb_priv->td_cnt++;
 	/* Giveback the urb when all the tds are completed */
 	if (urb_priv->td_cnt == urb_priv->length) {
-		ret = 1;
 		if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
 			xhci_to_hcd(xhci)->self.bandwidth_isoc_reqs--;
 			if (xhci_to_hcd(xhci)->self.bandwidth_isoc_reqs == 0) {
@@ -1947,9 +1945,10 @@ td_cleanup:
 					usb_amd_quirk_pll_enable();
 			}
 		}
+		xhci_giveback_urb_locked(xhci, td, *status);
 	}
 
-	return ret;
+	return 0;
 }
 
 /* sum trb lengths from ring dequeue up to stop_trb, _excluding_ stop_trb */
@@ -2259,7 +2258,6 @@ static int handle_tx_event(struct xhci_h
 	struct xhci_ep_ctx *ep_ctx;
 	struct list_head *tmp;
 	u32 trb_comp_code;
-	int ret = 0;
 	int td_num = 0;
 	bool handling_skipped_tds = false;
 
@@ -2437,7 +2435,6 @@ static int handle_tx_event(struct xhci_h
 				xhci_dbg(xhci, "td_list is empty while skip "
 						"flag set. Clear skip flag.\n");
 			}
-			ret = 0;
 			goto cleanup;
 		}
 
@@ -2446,7 +2443,6 @@ static int handle_tx_event(struct xhci_h
 			ep->skip = false;
 			xhci_dbg(xhci, "All tds on the ep_ring skipped. "
 						"Clear skip flag.\n");
-			ret = 0;
 			goto cleanup;
 		}
 
@@ -2468,7 +2464,6 @@ static int handle_tx_event(struct xhci_h
 		 */
 		if (!ep_seg && (trb_comp_code == COMP_STOP ||
 				   trb_comp_code == COMP_STOP_INVAL)) {
-			ret = 0;
 			goto cleanup;
 		}
 
@@ -2482,7 +2477,6 @@ static int handle_tx_event(struct xhci_h
 				if ((xhci->quirks & XHCI_SPURIOUS_SUCCESS) &&
 						ep_ring->last_td_was_short) {
 					ep_ring->last_td_was_short = false;
-					ret = 0;
 					goto cleanup;
 				}
 				/* HC is busted, give up! */
@@ -2497,7 +2491,7 @@ static int handle_tx_event(struct xhci_h
 				return -ESHUTDOWN;
 			}
 
-			ret = skip_isoc_td(xhci, td, event, ep, &status);
+			skip_isoc_td(xhci, td, event, ep, &status);
 			goto cleanup;
 		}
 		if (trb_comp_code == COMP_SHORT_TX)
@@ -2523,22 +2517,15 @@ static int handle_tx_event(struct xhci_h
 			goto cleanup;
 		}
 
-		/* Now update the urb's actual_length and give back to
-		 * the core
-		 */
+		/* update the urb's actual_length and give back to the core */
 		if (usb_endpoint_xfer_control(&td->urb->ep->desc))
-			ret = process_ctrl_td(xhci, td, ep_trb, event, ep,
-						 &status);
+			process_ctrl_td(xhci, td, ep_trb, event, ep, &status);
 		else if (usb_endpoint_xfer_isoc(&td->urb->ep->desc))
-			ret = process_isoc_td(xhci, td, ep_trb, event, ep,
-						 &status);
+			process_isoc_td(xhci, td, ep_trb, event, ep, &status);
 		else
-			ret = process_bulk_intr_td(xhci, td, ep_trb, event,
-						 ep, &status);
-
+			process_bulk_intr_td(xhci, td, ep_trb, event, ep,
+					     &status);
 cleanup:
-
-
 		handling_skipped_tds = ep->skip &&
 			trb_comp_code != COMP_MISSED_INT &&
 			trb_comp_code != COMP_PING_ERR;
@@ -2550,8 +2537,6 @@ cleanup:
 		if (!handling_skipped_tds)
 			inc_deq(xhci, xhci->event_ring);
 
-		if (ret)
-			xhci_giveback_urb_locked(xhci, td, status);
 	/*
 	 * If ep->skip is set, it means there are missed tds on the
 	 * endpoint ring need to take care of.